Heat exchangers used as part of the engine bleed air system comprise bundles of tubes housed in a casing, wherein a first flow of coolant fluid is generated in the space existing between the tubes and wherein a second flow of hot air flows through the tubes.
The heat exchangers, which are normally very voluminous, are usually installed in areas of limited available space, such as the pylon or nacelle of an aircraft. This is a drawback in the aeronautic industry which is constantly seeking to achieve smaller and lighter components.
Therefore, a different type of heat exchanger is used in order to solve the problem of space. These heat exchangers are fins and plates type, which also improve the thermal efficiency per volume, but as a drawback provide a higher stratification of the flow characteristics at their outlet. The hot air obtained from the heat exchanger is a stratified flow, not only thermally but also for different flow properties, which can damage different downstream systems in fluid communication with the heat exchanger.
These downstream systems require an incident homogeneous flow and adequate temperatures, so both a high stratification and extreme temperatures can damage them and impact in their performance.